Pneumatic hammer tool



Patented July 20, 1926.

UNITED STATES raarste PATENT OFFICE.

FRANCIS A. JIMERSON, OF ATHENS, PENNSYLVANIA, ASSIGNOR `TO INGERSOLL-R-AND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION 0F NEW' PNEUMATIC HAMMER TOOL.

Application led October 29, 1924.

This invention relates to pneumatic hammer tools, and more particularly to the arrangement of throttle valves and handles therefor. The object of the invention is to enable the operator to control the throttle valve by pressure on the handle, this same pressure being normally exerted in holding the tool against its work. Another object of the invention is to absorb the vibration of the tool in the handle.

Other objects of the invention will be in part obvious and in part pointed out in the following description taken in conjunction with the accompanying drawings, in which- Figure l is a longitudinal section through tool provided with a handle and throttlc valve constructed in accordance with the practice of the invention, and

Figure 2 is a longitudinal view partly in section showing the method of holding the tool and the manner in which the throttle valve is operated.

Referring to the drawings, the invention is shown as applied to a pneumatic hammer tool, commonly known as a coal pick, and comprises a cylinder A into the front end of which a sharp pointed steel B is adapted to be inserted. Within the cylinder A a piston O is adapted to reciprocate and strike against the inserted end of the steel B. The movements of the piston O are controlled by a valve D working in a valve chamber E set into the back of the cylinder A and provided with inlet ports l? and G leading to the rear and front ends of the cylinder respectively. The exhaust from the cylinder A is emitted through eX- haust ports H leading to atmosphere. The valve motion may be of any desiredtype, that shown here being more completely described in the copending application Serial No. 746,464 filed October 29, 1924. The

` flow of motive fluid to the valve chamber E is controlled by'athrottle valve which preferably includes a ball J interposed between a plunger K and a spring L and adapted to seat at the end of a bore O leading to a supply passage P connected to the valve chamber E. The spring L and the ball J are contained in a plug Q, screw threaded into the boss R on the side of the cylinder A. The boss R is also provided with a passage S leading to the bore O and also connecting with a suitable hose connection T. The plunger K extends through Serial No. 746,463.

the rear face of the boss R so as to be actuated by external means to open the passage for motive fluid from the passage S to the supply passage P and thence to the valve chamber. E by pressing the ball J against the force of the spring L from its seat at the end of the bore O rThe coal pick is controlled by a handle preferably at the rear of the cylinder A. This handle includes a loop U of resilient material, one end of the loop being clamped or anchored to the back head V of the cylinder A by means of bolts 7 and a cross piece X therebetween. The other end Y of the loop U is free to be pressed against the plunger K to operate the throttle valve. Preferably the anchored end of the loop terminates in a projecting end Z which prevents the free end Y from being pulled back further than is necessary to release the plunger K. Intermediate the ends of the loop U there is provided a grip b of aluminum, rubber, or other suitable material and of any suitable form comfortable to the operator.

One advantage of this construction is that the tool may be held, as shown in Figure 2, with one hand guiding the point of the steel B while the other hand is placed on the handle Z) and exerts the pressure at the rear end of the tool to hold the steel B against its work. This pressure is sutiicient to spring the loop U causing the free end Y to press against the plunger K and unseat the ball valve J (Figure 2) and thereupon to admit motive fluid to the valve chamber E for operating the piston O. No other pressure operation is necessary to open the throttle valve. When the operator desires to stop the operation of the hammer tool, he relieves the pressure on the grip whereupon the end Y of the loop U returns yto its normal position, (Figure l) releasing the plunger K and closing the throttle valve to cut ott the supply of motive fluid. The throttle valve thus responds to the natural and almost involuntary movements of the operator.

I claim:

l. A pneumatic hammer tool comprising a spring pressed throttle valve normally held closed, and a spring handle for holding the hammer tool against the work consisting of a single loop of resilientmaterial anchored at one end to the rear of the hammer tool and having the other end tree and contacting` with the said valve, and a stop for limiting` the rearward movement ott' the free end ot the handle.

2. A pneumatie hammer tool comprising a throttle valve provided with a spring pressed plunger and normally held closed, :1nd a handle for holding the hammer tool against the work consisting of a single loop ot resilient material, substantially elliptieal in shape, having one end anchored to the rear end ot the hammer, andthe other end normally adapted to Contact with the said springl pressed plunger, whereby downward pressure on the loop will cause the free end ol. the loop to force the plunger downwardly its spring and thereby open the said valve.

S. A pneumatic hammer tool Comprising` 20 a throttle valve provided with a spring` pressed plunger having` its end protruding 'from the rear end of the tool, and a handle for holding the tool against the Work oonsisting ot a single loop of resilient material, one end ot the loop being anchored at the rear or" the hammer and the other tree end being adapted to Contact with the end et the said plunger whereby downward pressure upon the said loop will press down the plunger, opening the valve and causing reeiproeation oli' the hammer`l while withdrawal of downward pressure on the said loop will release the plunger and stop reeiproeation of the hammer, and a grip on the loop intermediate thereof and a stop ttor limiting' the rearward movement of the 'free end ot the said loop.

ln testimony whereof l have signed this specification.

FYANCIS A. JIMEBSON. 

